pairing_program/src/ExamManager.java

import java.util.*;

public class ExamManager {
    private QuestionGenerator generator = new QuestionGenerator();
    private Set<String> history = new HashSet<>();
    private String type;

    public ExamManager(String type){
        this.type = type;
    }

    public List<String> generateExam(int numQuestions){
        List<String> questions = new ArrayList<>();
        for(int i=0;i<numQuestions;i++){
            String q;
            do {
                q = generator.generateQuestion(type);
            } while(history.contains(q));
            history.add(q);
            questions.add(q);
        }
        return questions;
    }
}